fix: tag count regression - remove double increment causing off-by-one error (#4800)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: boojack <24653555+boojack@users.noreply.github.com>

server/router/api/v1/test/user_service_stats_test.go

@@ -0,0 +1,105 @@
+package v1
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	v1pb "github.com/usememos/memos/proto/gen/api/v1"
+	storepb "github.com/usememos/memos/proto/gen/store"
+	"github.com/usememos/memos/store"
+)
+
+func TestGetUserStats_TagCount(t *testing.T) {
+	ctx := context.Background()
+	
+	// Create test service
+	ts := NewTestService(t)
+	defer ts.Cleanup()
+
+	// Create a test host user
+	user, err := ts.CreateHostUser(ctx, "test_user")
+	require.NoError(t, err)
+
+	// Create user context for authentication
+	userCtx := ts.CreateUserContext(ctx, user.ID)
+
+	// Create a memo with a single tag
+	memo, err := ts.Store.CreateMemo(ctx, &store.Memo{
+		UID:        "test-memo-1",
+		CreatorID:  user.ID,
+		Content:    "This is a test memo with #test tag",
+		Visibility: store.Public,
+		Payload: &storepb.MemoPayload{
+			Tags: []string{"test"},
+		},
+	})
+	require.NoError(t, err)
+	require.NotNil(t, memo)
+
+	// Test GetUserStats
+	userName := fmt.Sprintf("users/%d", user.ID)
+	response, err := ts.Service.GetUserStats(userCtx, &v1pb.GetUserStatsRequest{
+		Name: userName,
+	})
+	require.NoError(t, err)
+	require.NotNil(t, response)
+
+	// Check that the tag count is exactly 1, not 2
+	require.Contains(t, response.TagCount, "test")
+	require.Equal(t, int32(1), response.TagCount["test"], "Tag count should be 1 for a single occurrence")
+
+	// Create another memo with the same tag
+	memo2, err := ts.Store.CreateMemo(ctx, &store.Memo{
+		UID:        "test-memo-2", 
+		CreatorID:  user.ID,
+		Content:    "Another memo with #test tag",
+		Visibility: store.Public,
+		Payload: &storepb.MemoPayload{
+			Tags: []string{"test"},
+		},
+	})
+	require.NoError(t, err)
+	require.NotNil(t, memo2)
+
+	// Test GetUserStats again
+	response2, err := ts.Service.GetUserStats(userCtx, &v1pb.GetUserStatsRequest{
+		Name: userName,
+	})
+	require.NoError(t, err)
+	require.NotNil(t, response2)
+
+	// Check that the tag count is exactly 2, not 3
+	require.Contains(t, response2.TagCount, "test")
+	require.Equal(t, int32(2), response2.TagCount["test"], "Tag count should be 2 for two occurrences")
+
+	// Test with a new unique tag
+	memo3, err := ts.Store.CreateMemo(ctx, &store.Memo{
+		UID:        "test-memo-3",
+		CreatorID:  user.ID,
+		Content:    "Memo with #unique tag",
+		Visibility: store.Public,
+		Payload: &storepb.MemoPayload{
+			Tags: []string{"unique"},
+		},
+	})
+	require.NoError(t, err)
+	require.NotNil(t, memo3)
+
+	// Test GetUserStats for the new tag
+	response3, err := ts.Service.GetUserStats(userCtx, &v1pb.GetUserStatsRequest{
+		Name: userName,
+	})
+	require.NoError(t, err)
+	require.NotNil(t, response3)
+
+	// Check that the unique tag count is exactly 1
+	require.Contains(t, response3.TagCount, "unique")
+	require.Equal(t, int32(1), response3.TagCount["unique"], "New tag count should be 1 for first occurrence")
+	
+	// The original test tag should still be 2
+	require.Contains(t, response3.TagCount, "test")
+	require.Equal(t, int32(2), response3.TagCount["test"], "Original tag count should remain 2")
+}

server/router/api/v1/user_service_stats.go

@@ -128,9 +128,6 @@ func (s *APIV1Service) GetUserStats(ctx context.Context, request *v1pb.GetUserSt
 		// Count different memo types based on content.
 		if memo.Payload != nil {
 			for _, tag := range memo.Payload.Tags {
-				if tagCount[tag] == 0 {
-					tagCount[tag] = 1
-				}
 				tagCount[tag]++
 			}
 			if memo.Payload.Property != nil {